One vertex per element, one color per generator, with an edge from x to x·s.
(2,6)(7,8)(9,10,14,18)(11,16,21,15)(12,13,17,23)(19,22,24,20)(26,32)(28,35)(33,36)(37,39)(1,2)(3,7)(4,8)(5,6)(25,26)(27,36)(28,34)(29,33)(30,35)(31,32)(37,38)(39,40) involution — undirected(1,3,5,4)(2,7,6,8)(9,11)(10,15)(12,19)(13,20)(14,21)(16,18)(17,24)(22,23)(25,27,31,29)(26,33,32,36)(28,37,35,39)(30,38,34,40)(1,4,5,3)(2,8,6,7)(9,12,14,17)(10,13,18,23)(11,19,21,24)(15,20,16,22)(25,28,31,35)(26,34,32,30)(27,37,29,39)(33,40,36,38)(9,11)(10,16)(12,19)(13,22)(14,21)(15,18)(17,24)(20,23)(25,29,31,27)(26,33,32,36)(28,39,35,37)(30,38,34,40)(9,13)(10,17)(11,20)(12,18)(14,23)(15,24)(16,19)(21,22)(25,30,31,34)(26,35,32,28)(27,38,29,40)(33,39,36,37)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.